HDU3966(树链剖分) 模板题

呃…学习的话有个链接http://blog.sina.com.cn/s/blog_7a1746820100wp67.html
（对没错，我就是来贴代码的…因为CF有道题要用树链剖分所以 学习了一下

#include<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
#include<math.h>
#include<queue>
#include<stack>
#include<string>
#include<vector>
#include<map>
#include<set>
using namespace std;
#define rfor(i,a,b) for(i=a;i<=b;++i)
#define lfor(i,a,b) for(i=a;i>=b;--i)
#define sfor(i,a,h) for(i=h[a];i!=-1;i=e[i].next)
#define mem(a,b) memset(a,b,sizeof(a))
#define mec(a,b) memcpy(a,b,sizeof(b))
#define cheak(i) printf("%d ",i)
#define min(a,b) (a>b?b:a)
#define max(a,b) (a>b?a:b)
#define inf 0x3f3f3f3f
#define lowbit(x) (x&(-x))
typedef long long LL;
#define maxn 50010
#define maxm maxn*maxn
#define lson(x) (splay[x].son[0])
#define rson(x) (splay[x].son[1])
int n,m,q,tim;
int num[maxn],siz[maxn],top[maxn],son[maxn];
int dep[maxn],tid[maxn],Rank[maxn],fa[maxn];
struct node
{
    int next,sta,to;
}e[maxn*2];
int tot,h[maxn];
void add_edge(int a,int b)
{
    e[++tot].next=h[a];
    e[tot].sta=a;
    e[tot].to=b;
    h[a]=tot;
}
void init()
{
    mem(h,-1);mem(son,-1);
    tim=0;tot=0;
}
//树链剖分 
void dfs1(int u,int father,int d)
{
    dep[u]=d;fa[u]=father;
    siz[u]=1;
    for(int i=h[u];i!=-1;i=e[i].next)
    {
        int v=e[i].to;
        if(v!=father)
        {
            dfs1(v,u,d+1);
            siz[u]+=siz[v];
            if(son[u]==-1||siz[v]>siz[son[u]])
            son[u]=v;
        }
    }
}
void dfs2(int u,int tp)
{
    top[u]=tp;tid[u]=++tim;
    Rank[tim]=u;
    if(son[u]==-1) return ;
    dfs2(son[u],tp);
    for(int i=h[u];i!=-1;i=e[i].next)
    {
        int v=e[i].to;
        if(v!=son[u]&&v!=fa[u])
        dfs2(v,v);
    }
}
//segment
struct Tree
{
    int sum,col;
}tree[maxn*4]; 
void Push_up(int index)
{
    tree[index].sum=max(tree[index*2].sum,tree[index*2+1].sum);
}
void Push_down(int index,int k)
{
    if(tree[index].col)
    {
        tree[index*2].col+=tree[index].col;
        tree[index*2+1].col+=tree[index].col;
        tree[index*2].sum+=(k-k/2)*tree[index].col;
        tree[index*2+1].sum+=(k/2)*tree[index].col;
        tree[index].col=0;
    }
}
void build(int l,int r,int index)
{
    tree[index].col=0;
    if(l==r)
    {
        tree[index].sum=num[Rank[l]];
        return ;
    }
    int mid=(l+r)/2;
    build(l,mid,index*2);
    build(mid+1,r,index*2+1);
    Push_up(index);
}
int query(int l,int r,int index,int val)
{
    if(l==r) return tree[index].sum;
    Push_down(index,r-l+1);
    int mid=(l+r)/2;
    int ret=0;
    if(val<=mid)
    ret=query(l,mid,index*2,val);
    else ret=query(mid+1,r,index*2+1,val);
    Push_up(index);
    return ret;
}
void update(int L,int R,int val,int l,int r,int index)
{
    if(L<=l&&R>=r)
    {
        tree[index].col+=val;
        tree[index].sum+=val*(r-l+1);
        return ;
    }
    Push_down(index,r-l+1);
    int mid=(l+r)/2;
    if(L<=mid)
    update(L,R,val,l,mid,index*2);
    if(R>mid)
    update(L,R,val,mid+1,r,index*2+1);
    Push_up(index);
}
void Change(int x,int y,int val)
{
    while(top[x]!=top[y])
    {
        if(dep[top[x]]<dep[top[y]]) swap(x,y);
        update(tid[top[x]],tid[x],val,1,n,1);
        x=fa[top[x]];
    }
    if(dep[x]>dep[y]) swap(x,y);
    update(tid[x],tid[y],val,1,n,1);
}
int main()
{
    int i,k,a,b,c;
    while(~scanf("%d%d%d",&n,&m,&k))
    {
        init();
        rfor(i,1,n) scanf("%d",&num[i]);
        rfor(i,1,m)
        {
            scanf("%d%d",&a,&b);
            add_edge(a,b);add_edge(b,a);
        }
        dfs1(1,0,0);
        dfs2(1,1);
        build(1,n,1);
        while(k--)
        {
            char oper[5];
            scanf("%s",oper);
            if(oper[0]=='Q')
            {
                scanf("%d",&a);
                printf("%d\n",query(1,n,1,tid[a]));
            }
            else
            {
                scanf("%d%d%d",&a,&b,&c);
                if(oper[0]=='D') c=-c;
                Change(a,b,c);
            }
        }
    }
    return 0;
}